Steel moment frame connections are vital in moment frames designed to resist forces transferred from adjoining beams and columns. The welded unreinforced flange-welded web (WUF-W) connection is one of the pre-qualified connections used for steel special moment frames (SMFs). This study developed drift-based fragility functions for WUF-W connections based on test data of 35 WUF-W connection specimens from ten previous experimental studies. Four different damage states were defined to calculate the fragility: onset of yielding, local buckling, strength loss, and fracture. Fragility functions were derived assuming that lognormal distribution was validated using the Kolmogorov-Smirnov (K-S) test. It was confirmed that fragility functions for WUF-W connections were accurately proposed within a specified confidence interval. The fragility functions proposed in this study exhibit smaller standard deviations compared to FEMA P58, thereby reducing the likelihood of overestimating or underestimating damage at specific drift ratios. Furthermore, these functions remain within the confidence intervals across all damage states, contributing to improved accuracy in damage analysis and loss estimation in performance-based earthquake engineering.

A B S T R A C T
1. 서 론
2. WUF-W 접합부 데이터베이스
3. 손상수준 정의
    3.1 손상수준 1(Damage state 1): 경미한 손상(부재가 항복한 시점의 변위비)
    3.2 손상수준 2(Damage state 2): 보통 손상(최대내력 도달한시점에서의 변위비)
    3.3 손상수준 3(Damage state 3): 극심한 손상(20% 내력저하가발생한 시점에서의 변위비)
    3.4 손상수준 4(Damage state 4): 파단
4. 취약도 함수
5. 결 론
감사의 글
REFERENCES

• 이의재(한양대학교 건축공학과 석사과정) | Lee UiJae (Graduate Student, Department of Architectural Engineering, Hanyang University)
• 조은선(한양대학교 건축공학과 박사후 연구원) | Cho EunSeon (Post-doctoral Researcher, Department of Architectural Engineering, Hanyang University)
• 한상환(한양대학교 건축공학과 교수) | Han Sang Whan (Professor, Department of Architectural Engineering, Hanyang University) Corresponding author